Local structure study of multiferroic BiMn2O5 with EXAFS

GILBERTO FERNANDES LOPES FABBRIS; EDUARDO GRANADO; NESTOR E. MASSA; JOSE A. ALONSO; GUSTAVO AZEVEDO

Campinas, SP, Brasil

Workshop; XIX Reunion Anual de Usuarios del Laboratorio Nacional de Luz Sincrotron; 2009

Laboratorio Nacioal de Luz Sincrotron

ferromagnetism and ferroelectricity. These compounds have attracted a great deal of interest in recent years because of their potential applications as multiple state memory devices (i. e., information storage and manipulation via magnetic and electric ¯elds) as well as due to the complex interplay between lattice degrees of freedom and magnetic ordering, which remains poorly understood. Here we report on temperature dependent EXAFS measurements utilized to investigate the local structure of BiMn2O5 with magnetic and ferroelectric order in the interval from2O5 with magnetic and ferroelectric order in the interval from »40 K to »10 K. These were performed on transmission mode of both Mn (K-edge) and Bi (L3 edge) at beamline XAFS2 at LNLS, in the temperature range from 20K to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). and Bi (L3 edge) at beamline XAFS2 at LNLS, in the temperature range from 20K to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). and Bi (L3 edge) at beamline XAFS2 at LNLS, in the temperature range from 20K to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006). [3] T.A. Tyson et al., Phys. Rev. B 75, 174413 (2007). [4] E. Granado et al., Phys. Rev. B 77, 134101 (2008). to 300K, encompassing the multiferroic transition temperature . The Mn-K edge reveals a very small temperature dependence of the Debye-Waller factor suggesting that the MnO polyhedra are rigid. Above 125 K, in qualitative agreement with mea- surements for TbMn2O5 by Tyson et al [3], our results show structural distortions in the ¯rst coordination shell at the Bi L3 egde. This and synchrotron radiation XRD analysis [4] also suggest that low energy vibrational modes associated with low temperature MnO polyhedra rigid rotations might correlate with an anoma- lous linear expansion coe±cient in the same temperature range. Local structural distortions associated with the ferroelectric phase transition around 40K could not be identi¯ed, suggesting that any local structure change at this transition is very small. [1] A. F. Garc¶³a Flores et al., Phys Rev. B 73, 104411 (2006). [2] C. R. de la Cruz et al., J. of Appl. Phys. 99, 08R103 (2006)